Can't download "Create" through the launcher

We have just started using Omniverse “LumenRT for Omniverse” to be exact, for some reason even after checking with our IT dep. that the firewall was not causing an issue, I can’t seem to install “create” from the launcher along with some of the free “content” stuff too.

we have checked the logs and the common error is this one:
Error occurred in handler for ‘prepare-install’: FetchError: request to failed, reason: self signed certificate in certificate chain
at ClientRequest.

We need to use create to trial “Cesium” for our workflow, could anyone here tell me why it wouldn’t install from the launcher,

we meet all other min. hardware requirements ect.

Thank you